Computer-assisted face-jaw-teeth transplantation

ABSTRACT

A computer-assisted surgical system can include a donor sub-system and a recipient sub-system. The donor sub-system includes a first reference unit having a first trackable element, a fragment reference unit having a second trackable element, and a first detector configured to provide at least one of a first signal corresponding to a detected location of one or more of the first trackable element and the second trackable element. The recipient sub-system includes a second reference unit having a third trackable element, and a second detector configured to provide at least one of a second signal corresponding to a detected location of at least the third trackable element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 15/100,258,filed May 27, 2016, now U.S. Pat. No. 10,537,337 which is a U.S.National Stage application of PCT/US2014/067504 filed 25 Nov. 2014,which claims priority to U.S. Provisional patent application 61/910,204filed 29 Nov. 2013, U.S. provisional application 61/940,196 filed 14Feb. 2014, and U.S. provisional application 62/049,866 filed 12 Sep.2014, the entire disclosures of which are hereby incorporated byreference in their entireties.

GOVERNMENT SUPPORT STATEMENT

This invention was made with government support under Grant Nos.TR000424 and TR001079 awarded by the National Institutes of Health(NIH). The government has certain rights in the invention.

FIELD OF THE INVENTION

This invention relates generally to the field of surgery, particularlycraniomaxillofacial surgery, and specifically to the field ofcomputer-assisted craniomaxillofacial surgery and all relatedorthognathic, neurosurgical and head/face/neck surgical procedures andassociated methods, tools, and systems.

BACKGROUND OF THE INVENTION

Facial transplantation represents one of the most complicated scenariosin craniomaxillofacial surgery due to skeletal, aesthetic, and dentaldiscrepancies between donor and recipient. Use of computer technology toimprove accuracy and precision of craniomaxillofacial surgicalprocedures has been described for nearly 30 years, since the increasingavailability of computed topography (CT) prompted the development of aCT-based surgical simulation plan for osteotomies.

Two broad approaches to computer-assisted surgery (CAS) have gainedpopularity: 1) pre-operative computer surgical planning and the use ofthree-dimensional computer manufactured surgical guides (3D CAD/CAM) tocut and reposition bone and soft tissue, and 2) utilizing intraoperativefeedback relative to preoperative imaging for the surgeon to providemore objective data on what is happening beyond the “eyeball test.”However, none are meant for real-time placement feedback in areas whereguide placement is more challenging, such as the three-dimensionalfacial skeleton. Also, there are no single platforms built to provideBOTH planning AND navigation—with seamless integration. Additionally,standard off-the-shelf vendor computer-assisted surgery systems may notprovide custom features to mitigate problems associated with theincreased complexity of this particular procedure. Furthermore, thereare currently no validated methods for optimizing outcomes related tofacial (e.g., soft tissue), skeletal (e.g., hard tissue), and occlusal(e.g., dental) inconsistencies in the setting of donor-to-recipientanthropometric mismatch—a major hurdle to achieving this specialty'sfull potential.

One known system includes pre-operative planning and cutting guides byway of computer manufactured stereolithographic models for human facialtransplantation. However, such a system uses standard off-the-shelfvendor systems and does not include necessary features to mitigate theincreased complexity of this particular procedure.

Additionally, known CAS paradigms for craniomaxillofacial surgeryprovide little capacity for intraoperative plan updates. This featurebecomes especially important since, in some circumstances during thetransplantation surgery, it may be necessary to revise and update thepreoperative plans intraoperatively.

What is needed in the art, therefore, is a single, fully-integratedplatform, providing a computer-assisted surgery solution customized forpre-operative planning, intraoperative navigation, and dynamic,instantaneous feedback, for example, in the form of biomechanicalsimulation and real-time cephalometrics, for facial transplantation thataddresses common shortcomings of existing CAS systems and has thepotential to improve outcomes across both the pediatric and adult-basedpatient population.

SUMMARY

In an embodiment, there is a computer-assisted surgical system. Thesystem can include a donor sub-system and a recipient sub-system. Thedonor sub-system includes a first reference unit having a firsttrackable element, a fragment reference unit having a second trackableelement, and a first detector configured to provide at least one of afirst signal corresponding to a detected location of one or more of thefirst trackable element and the second trackable element. The recipientsub-system includes a second reference unit having a third trackableelement, and a second detector configured to provide at least one of asecond signal corresponding to a detected location of at least the thirdtrackable element.

In another embodiment, there is a computer-assisted, transplantationmethod. The method can include attaching a first reference unit having afirst trackable element to a first anatomical feature of a donor being,attaching a fragment reference unit having a second trackable element toa second anatomical feature of the donor, detecting a location of atleast one of the first trackable element and the second trackableelement with a first detector. The first detector may be configured toprovide at least one of a first signal corresponding to the detectedlocation of at least one of the first trackable element and the secondtrackable element. The method may further include accessing a firstcomputer readable reconstruction of the donor anatomy. The firstcomputer readable reconstruction includes a first orientation that isupdated based on a physical location of at least one of the firsttrackable element and the second trackable element as detected by thefirst detector. The method may further include attaching a secondreference unit having a third trackable element to an anatomical featureof a recipient being and detecting a location of the third trackableelement with a second detector. The second detector may be configured toprovide at least one of a second signal corresponding to a detectedlocation of at least the third trackable element. The method may furtherinclude accessing a second computer readable reconstruction of therecipient anatomy. The second computer readable reconstruction mayinclude a second orientation that is updated based on a physicallocation of the third trackable element detected by the second detector.The method may further include superimposing a first virtual donorfragment of the first computer readable reconstruction on the secondcomputer readable reconstruction.

Additional advantages of the embodiments will be set forth in part inthe description which follows, and in part will be understood from thedescription, or may be learned by practice of the invention. Theadvantages will be realized and attained by means of the elements andcombinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description, serve to explain the principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a surgical system and method that closes theloop between surgical planning, navigation, and enabling intraoperativeupdates to a surgical plan.

FIGS. 2A-2C provide a schematic overview of a surgical system.

FIGS. 2D-2G are graphical representations of some components and/orfeatures of the surgical system of FIGS. 2A-2C.

FIG. 3 is a flow chart depicting a procedure associated with use of thesurgical system, for example, the surgical system of FIGS. 2A-2C.

FIG. 4A is a CT-scan of reconstructed images of a size-mismatched facialskeleton generated from segmentation software utilized for pre-operativeplanning.

FIG. 4B shows a segmented arterial system of a craniomaxillofacialskeleton generated from CT angiography (CTA) data allowing 3D,intraoperative mapping.

FIGS. 5A-5B show depictions of on-screen images provided by a surgicalsystem, such as the surgical system of FIG. 2A displaying real-time,dynamic cephalometrics and pertinent measurements applicable to humans.FIG. 5A shows a donor's face-jaw-teeth alloflap in suboptimal positionas compared to a recipient's cranium. FIG. 5B shows appropriateface-jaw-teeth positioning with immediate surgeon feedback and updatedcephalometric data pertinent to a pre-clinical investigation. A surgeonmay adjust the position of face-jaw-teeth segment upwards, downwards,forwards, or backwards based on this real-time cephalometric feedback,as this information helps to predict optimal form and function. Forinstance, placing the face-jaw-teeth segment forward may improve thepatient's airway, but if moved too far forward, it may cause the patientto have a significant overjet (i.e. malocclusion) and abnormalappearance in a profile view.

FIG. 6 shows some pre-bent fixation plates with screw holes designedvirtually to accommodate the donor-to-recipient skeletal mismatch areasand matching navigational cutting guides of a surgical system, forexample, the surgical system of FIGS. 2A-2C.

FIG. 7A shows a kinematic reference mount of an embodiment as it isaffixed onto a donor's cranium with intermaxillary screws. A permanentsuture (not visible) attaches stabilizers, such as springs and/or crossbars, which allow easy removal and replacement during surgery.

FIG. 7B shows a detachable rigid body with reflective markers attachedto the reference body.

FIGS. 8A-8C are illustrations of cutting guides of the embodiments withnavigational capabilities. FIG. 8A illustrates a donor face-jaw-teethalloflap recovery, FIG. 8B shows a recipient preparation prior totransplant, and FIG. 8C illustrates a custom pre-bent fixation plate andpalatal splint designed to achieve face-jaw-teeth alignment and skeletalinset.

FIGS. 9A-9D are renderings showing exemplary surgical results.

FIGS. 10A-10C are a top-view (bird's eye view), a left-sided profileview, and a frontal view, respectively, of images displayed by animaging system of a surgical system. The images depict a recipientskeleton and include real-time assessment of planned versus actualface-jaw-teeth positions.

FIGS. 11A-11B are “on screen” images displayed by an imaging sub-systemof a surgical system. The images depict an ideal location of a cuttingguide versus an actual position and an actual inset position of a donoralloflap for aesthetic, dental, and skeletal relation in size-mismatcheddonors due to anterior translation of cutting guide.

FIGS. 12A-H illustrate a virtual osteotomy and planned cut planeplacement on virtual representations of a skeletal feature.

FIGS. 13A-13D illustrate a virtual placement of a cutting guidealongside (FIGS. 13A-13B) and illustrated representations of an actualplacement (FIGS. 13C-13D).

FIG. 14A illustrates a perspective view of a variation of a cuttingguide, for example, a variation of the cutting guide of FIG. 13.

FIG. 14B illustrates a top view of a variation of a cutting guide, forexample, a variation of the cutting guide of FIG. 13.

FIGS. 15A-15C provide a schematic overview of a surgical system similarto that of FIGS. 2A-2C.

FIGS. 15D-15H are graphical representations of some components and/orfeatures of the surgical system of FIGS. 15A-15C.

FIG. 16 is a flow chart depicting instructions that may be executed by aprocessor.

FIG. 17 is a flow chart depicting instructions that may be executed by aprocess.

FIG. 18 is a flow chart depicting a surgical method.

FIG. 19 is a flow chart depicting a surgical method.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all sub-ranges subsumedtherein. For example, a range of “less than 10” can include any and allsub-ranges between (and including) the minimum value of zero and themaximum value of 10, that is, any and all sub-ranges having a minimumvalue of equal to or greater than zero and a maximum value of equal toor less than 10, e.g., 1 to 5. In certain cases, the numerical values asstated for the parameter can take on negative values. In this case, theexample value of range stated as “less that 10” can assume negativevalues, e.g. −1, −2, −3, −10, −20, −30, etc.

The following embodiments are described for illustrative purposes onlywith reference to the figures. Those of skill in the art will appreciatethat the following description is exemplary in nature, and that variousmodifications to the parameters set forth herein could be made withoutdeparting from the scope of the present invention. It is intended thatthe specification and examples be considered as examples only. Thevarious embodiments are not necessarily mutually exclusive, as someembodiments can be combined with one or more other embodiments to formnew embodiments.

Disclosed are embodiments of a computer-assisted surgery system thatprovides for large animal and human pre-operative planning,intraoperative navigation which includes trackable surgical cuttingguides, and dynamic, real-time instantaneous feedback of cephalometricmeasurements/angles as needed for medical procedures, such as facialtransplantation, and many other instances of craniomaxillofacial andorthognathic surgery. Such a system can be referred to as acomputer-assisted planning and execution (C.A.P.E.) system and can beexploited in complex craniomaxillofacial surgery like Le Fort-based,face-jaw-teeth transplantation, for example, and any type oforthognathic surgical procedure affecting one's dental alignment, andcan include cross-gender facial transplantation.

The fundamental paradigm for computer-assisted surgery (CAS) involvesdeveloping a surgical plan, registering the plan and instruments withrespect to the patient, and carrying out the procedure according to theplan. Embodiments described herein include features for workstationmodules within a CAS paradigm. As shown in FIG. 1, a surgical system ofthe embodiments can enable intraoperative evaluation of a surgical planand can provide instrumentation for intraoperative planupdates/revisions when needed.

Embodiments can include a system with integrated planning and navigationmodules, for example, a system for tracking donor and recipient surgicalprocedures simultaneously. In general, features of such a system caninclude: 1) two or more networked workstations concurrently used inplanning and navigation of the two simultaneous surgeries for both donorand recipient irrespective of geographic proximity, 2) two or moretrackers, such as electromagnetic trackers, optical trackers (e.g.,Polaris, NDI Inc.), and the like, for tracking bone fragments, tools,and soft tissues, 3) one or more guides, reference kinematic markers,etc. as required for navigation. These features are described in furtherdetail with respect to FIGS. 2A-2G.

Preoperative planning can include the following tasks: a) segmentationand volumetric reconstruction of the donor and recipient facial anatomy;b) planning for patient-specific cutting guide placement; c)cephalometric analysis and biomechanical simulation of the hybridskeleton's occlusion and masticatory function, respectively; d)fabrication of the hybrid cutting guides enabling both geometric(“snap-on” fit) and optical navigation; e) 3D mapping the vascularsystem on both recipient and donor facial anatomy; and f) plan updates,if necessary, based on the feedback from the intraoperative module. Asused herein, “snap-on fit” or “snap-on” or “snap on” are used todescribe the way an item, such as a cutting guide, attaches to apre-determined area. That is, the cutting guide actually “snaps-on” to acertain pre-determined area along the patient being's anatomy, such asthe facial skeleton, and in all other areas it doesn't fit properlysince size and width varies throughout significantly with manyconvexities and concavities.

Intraoperative tasks of embodiments described herein can generallyinclude: 1) registering the preoperative model reconstructed from the CTdata to donor and recipient anatomy; 2) visualizing (e.g., usinginformation from the tracker, such as an electromagnetic tracker,optical tracker, and the like) the instruments and cutting guides tohelp the surgeon navigate; 3) verifying the placement of cutting guides,and performing real-time cephalometric and biomechanical simulation forocclusion analysis, if, for any reason, the osteotomy sites need to berevised; 4) dynamically tracking the attachment of the donor fragment tothe recipient and providing quantitative and qualitative (e.g., visual)feedback to the surgeon for the purpose of improving final outcomesrelated to form (i.e., overall facial aesthetics) and function (i.e.,mastication, occlusion relation, airway patency). Such a procedure isdescribed in further detail below with respect to FIG. 3.

Preoperative Planning

In general, a method for performing a surgery includes a virtualsurgical planning step that includes performing segmentation and 3Dreconstruction of recipient and donor CT scans (e.g., Mimics 15.01,Materialise, Leuven Belgium). Virtual osteotomies can then be performedwithin the software to optimize the donor/recipient match.Patient-customized cutting guide templates can then be created (3-matic7.01, Materialize, Leuven, Belgium). These templates can then berapid-prototyped via an additive manufacturing modeling process, whichcan include, but is not limited to, stereolithography or 3D printing andthe like. The surgical method and system for performing surgery aredescribed in further detail below.

Referring to FIGS. 4A and 4B, during the initial planning stage,surgeons determine a virtual plan 401 based on the recipient'scraniomaxillofacial deformity irrespective of the donor. From registeredCT data, segmentation software generates volume data for specific keyelements (e.g., the mandible, maxilla, and cranium) used forpreoperative planning and visualization. The planning workstationautomatically generates the expected cut geometry of the donor fragment402 together with the recipient, thereby defining the predicted facialskeleton with accompanying hybrid occlusion. If available, blood vessels404 are segmented from CT angiography scans as shown in FIG. 4B. Thatis, in an embodiment, nerves (via known nerve foramens) and vessels(both arteries and veins) can be localized to provide a full anatomical“road map” to the surgeons for a more precise, time-saving anatomicaldissection with perhaps decreased blood loss and smaller incisions. Theplanning module can also perform static cephalometric analysis andevaluation of face-jaw-teeth harmony via biomechanical simulation onvarying constructions of the hybrid donor and recipient jaws, such asthat shown in FIGS. 5A-5B. Using this tool, the surgeon can evaluatedifferent placements for the donor's face-jaw-teeth alloflap on therecipient's facial skeleton in relation to orbital volumes, airwaypatency, facial projection, and dental alignment. An automatedcephalometric computation for the hybrid face indicates the validity ofthe planned surgery from both an aesthetic, functional andreconstructive standpoint based on various measurements of pertinentlandmarks as shown, for example, in Tables 1A-B.

TABLE 1A Pertinent landmarks for cephalometric analysis SYM- BOL NAMEand DEFINITION Go Gonion: a point mid-way between points defining anglesof the mandible Gn Gnathion: most convex point located at the symphysisof the mandible ALV Alveolare: mid-line of alveolar process of the upperjaw, at incisor - alveolar junction LIB Lower Incisor Base: midline ofanterior border of alveolar process of mandible at the incisor-alveolarjunction PA Parietale: most superior aspect of skull in the midline,(formed by nuchal crest of occipital bone and parietal bone) PRNPronasale: bony landmark representing anterior limit of nasal bone ZYZygion: most lateral point of malar bone OCC Occipital region: midpointbetween the occipital condyles

TABLE 1B Cephalometric measurements and related units. Measure ZY- PA-Go- Go- PA- LIB- Overbite Overjet OCC- LIB- PA- PA- ALV- ZY PRN Gn LIBALV ALV PRN PA- PRN- PRN- PRN- ALV ALV LIB LIB Units mm mm mm Mm mm mmMm mm mm deg deg deg deg

To evaluate and predict cephalometric relationships both during planningand intra-operative environments, the system can use validated,translational landmarks between swine and human to thereby alloweffective pre-clinical investigation. The cephalometric parametersdefined by these landmarks can be automatically recalculated as thesurgeon relocates the bone fragments using a workstation's graphicaluser interface.

Preoperative planning can also involve fabrication of custom guides 207(as shown in FIG. 6) and palatal splints 223 (as shown in FIG. 8C).Planned cut planes 403 (as shown in FIG. 4) can be used for defining thegeometry of the cutting guides to thereby provide patient-specificcutting guides. These cutting guides can be designed according to theskeletal features through which the cutting plane intersects, such as anouter skeletal surface of a cross section defined by the cutting plane,and can be fabricated via stereolithography, or via any additivemanufacture technology. In an embodiment, custom cutting guide templatescan be separately designed and navigational registration elements can beadded (Freeform Plus, 3D Systems, Rock Hill, S.C.). As discussed above,the surgical guides can be manufactured via additive manufacturingtechnology (AMT). The cutting guides can, therefore, be a 3D printingmaterial such as a polymer, and can include an attachment surface 216configured for attaching to a skeletal feature, and can have a “snap-on”fit to both donor and recipient. As described above, the attachmentsurface may include a contoured surface that corresponds to the contoursof the skeletal feature within the planned cut planes. A navigationsurface, such as a reference geometry 217 connected, built into, orattached to the guide structure directly or via attachment guides (notshown), enables dynamic intraoperative tracking of guides with respectto the patient's skeleton. Palatal splints ensure planned dento-skeletalalignment fixation following Le Fort-type facial transplants or anysimilar type of surgery. Fixation plates 216 can include a primarysurface 216′ and a plurality of fixation surfaces 221, such as eyelets,for screw placement to provide rigid immobilization at the irregularskeletal contour areas along various donor-to-recipient interfaces.Having pre-bent fixation plates decreases total operative times andhelps to confirm accurate skeletal alignment by overcoming step-offdeformities at bone-to-bone interfaces. Accordingly, at least one of theplurality of fixation surfaces can be located on one side of the primarysurface and configured for attaching the fixation surface to a donorskeleton fragment, and at least one of another of the plurality offixation surfaces is located on another side of the primary surface andconfigured for attaching the fixation surface to a recipient skeleton.The whole fixation plate or just portions of the fixation plate, such asthe primary surface or fixation surfaces can be manufactured viaadditive manufacturing technology.

The cutting guide's navigation surface can include trackable objects,for example, on the reference geometry, such as infrared (IR) reflectivecoatings or IR emitters. For example, the trackable objects can includea plurality of integrated tracking spheres, each of which has an IRreflection surfaces.

Intraoperative Surgical Assistance

Individual navigation for both donor and recipient surgeries tracks thecutting guides with respect to planned positions. Surgeons can attach areference unit, such as a kinematic reference mount to threeintramedullary fixation (IMF) screws arranged in a triangular pattern oneach the donor and recipient craniums as shown in FIG. 7A-7B.Accordingly, in an embodiment, there is a reference unit 205 forproviding real-time surgical navigation assistance. The reference unitfor providing real-time surgical navigation assistance can include akinematic mount 203, at least one fixation rod 202, at least one support204, and reference geometry 201. The kinematic mount 203 can include abase with a plurality of recesses defined by sidewalls 233, at least onepair of slots 235 defined by portions of the sidewalls, with each slotof the pair formed across the recess from the other slot, and at leastone guide hole 237 extending through a length of the fixation plate. Theat least one fixation rod 202 can extend through the at least one guidehole 237. An end of the at least one support rod can be configured forattaching to a skeleton of a being 209. The at least one support can bedisposed in the pair of slots and can be configured to attach to thebeing. The reference geometry 201 can be attached to the at least onefixation rod.

The at least one support 204 can include at least one cross-bar 204′with ends that are configured for placement in the slots 235, and aspring 204″ attached at one end to the at least one cross-bar 204′ andattached at another end to the patient (e.g., a human-being). The springattached at another end to the being can be attached via a suture(further described below). The reference unit 205 can further include atrackable object disposed on the reference geometry. The trackableobject disposed on the reference geometry can include an IR reflectivesurface. The mount 203 can be made via additive manufacturing techniquesand can therefore include a polymer. The at least one fixation rod caninclude a plurality of intramedullary fixation screws. The base can beconfigured for being detachably mounted on the skeleton of the being209. The intramedullary fixation screws can be arranged in a triangularpattern. Accordingly the guide-holes can be configured in a triangularpattern on the base.

Accordingly, the mount design permits flexibility in the placement ofthe IMF screws so that no template is necessary. A spring 204″ canattach to each IMF screw via suture threaded through, for example, theeyelets. These springs hold the cranial mount 203 in place and alloweasy removal and replacement of the cranial mount (e.g. duringpositional changes required for bone cuts and soft tissue dissections).This may provide detachability and use of Intramaxillary fixation (IMF)screws for stable attachment

The reference geometry 201 (e.g., which can be purchased from Brainlab,Westchester, Ill., USA) attached to the kinematic mount 203 provides astatic coordinate frame attached to the patient. The surgeon candigitize three bony landmarks (e.g., the inferior aspect of the orbitsand antero-superior maxilla) to define a rough registration between theenvironment and virtual models. For example, three, consistent pointscan be selected which can be quick to find, easy to reproduce onnumerous occasions, and would remain constant irrespective of the userand his/her experience with the systems of the embodiments. The surgeoncan thereby collect several point sets from exposed bone using adigitization tool and uses an iterative closest point registrationtechnique to refine the registration. As shown in FIG. 8, onceregistered, the surgeon navigates the placement of the cutting guide 217using the combination of “snap-on” geometric design and the trackingsystem coupled to visual feedback. This allows assessment ofinaccuracies related to soft tissue interference, iatrogenicmalpositioning, and anatomical changes since acquiring original CT scandata, and/or imperfections in cutting guide design or additivemanufacturing process.

Self-drilling screws affix the cutting guide to the patient's skeletonto ensure osteotomies are performed along pre-defined planes, maximizingbony congruity. After dissecting the donor's maxillofacial fragment andpreparing the recipient's anatomy, the surgical team transfers thefacial alloflap. The system is configured to track the finalthree-dimensional placement of, for example, the Le Fort-based alloflapproviding real-time visualization such as that shown in FIG. 5A-5B. Thisprovides real-time visualization of important structures such as neworbital volumes (vertical limit of inset), airway patency (posteriorhorizontal limit of inset), and facial projection (anterior horizontallimit of inset). Once confirmed, the surgeon fixates the donor alloflapto the recipient following conventional techniques with plates andscrews.

Accordingly, returning to FIGS. 2A-2G, there is a system 200 fortracking donor and recipient surgical procedures simultaneously. Thesystem can include a donor sub-system 200-D, a recipient sub-system200-R and a communications link (indicated by the horizontaldotted-line) such as a communication link that provides TCP/IP datatransfer between the donor and recipient sub-systems. The donorsub-system can include a first computer workstation 215-D, a firstcranial reference module 205-D, a first cutting guide 207-D forattaching to a preselected location of a donor skeleton 206, a firstfragment reference module 201-D′, and a first tracker 213-D. The firstcutting guide 207-D can include an attachment surface 219-R configuredfor attaching to a skeletal feature, and a navigation surface 217-Dconnected to the attachment surface and comprising a trackable referencegeometry. The first tracker 213-D may be configured to be incommunication with the first computer workstation, for example, via acommunications link. The first tracker can be configured to track, forexample via IR optical tracking, a location of a portion of the firstcranial reference module, a portion of the first cutting guide and aportion of the first fragment reference module. The recipient sub-system200-R can include a second computer workstation 215-R, a second cranialreference module 205-R, and a second tracker 213-R. The second tracker213-R can be configured to be in communication with the second computerworkstation, for example, via a communications link. The second trackercan be configured to track, for example, via IR optical tracking, alocation of a portion of the second cranial reference module. Thecommunications link can connect the first computer workstation and thesecond computer workstation such that the first computer workstation andsecond computer workstation are able to communicate.

The recipient sub-system 200-R can further include a second fragmentreference unit 201-R. The second tracker 213-R can further be configuredto track a location of a portion of the second fragment unit.

The recipient sub-system 200-R can further include a second cuttingguide 219-R for attaching to a preselected location of a recipientskeleton 208. The second tracker 213-R can further be configured totrack a location of a portion of the second cutting guide.

Additionally, when a surgeon has removed the donor skeletal fragmentfrom the donor, it can then be transferred for attachment onto therecipient. Accordingly, the second tracker 213-R can be furtherconfigured to track a location of a portion of the first cutting guide207-D so that it can be matched relative a position of the secondcranial reference module 205-R.

The first cranial reference unit, the second cranial reference unit, orboth the first and second cranial reference units can include akinematic mount 205 as described above.

Using the system of FIGS. 2A-2G, it is possible to execute a surgicalmethod, such as the surgical method described in FIG. 3. For example, instep 302 a donor, recipient and transplant type are identified. CT/CTAscans of both the donor and recipient are collected and 3D models arecreated in step 304. The donor and recipients are prepared for surgerywith the creation of skin incisions in step 306. The method continues at307 with attachment of reference guides and performing registration. Forexample, a first cranial reference unit can be attached to a donorskeleton, a first fragment reference unit can also be attached to thedonor skeleton at a location that is different that of the first cranialreference unit. The locations of the first cranial reference unit andthe first fragment reference unit can be tracked with a first tracker.3D reconstructions of the donor skeleton can be constructed showing afirst virtual cranial reference unit and first virtual fragmentreference unit superimposed on the first 3D reconstruction at locationsthat correspond to relative positions of the first cranial referenceunit and the first fragment reference unit.

A second cranial reference unit can be attached to a recipient skeleton.A second location of the second cranial reference unit can be trackedwith a second tracker. A second 3D reconstruction of the recipientskeleton can be created with a second virtual cranial reference unitsuperimposed on the second 3D reconstruction at a location thatcorresponds to a location of the second cranial reference unit. At 308,vessels and nerves are dissected and exposed. At this stage, navigationof the patient-specific cutting guides can occur, with plan revision andupdates provided periodically. For example, a first cutting guide, suchas a patient-specific cutting guide according to the descriptionsprovided above, can be attached onto the donor skeleton at a preselectedlocation such as that corresponding to a planned cut-plane. The locationof the first cutting guide can be tracked with the first tracker. Afirst virtual cutting guide can be superimposed on the first 3Dreconstruction at a location that corresponds to a location of the firstcutting guide relative to the location of the first cranial referenceunit or the location of the first fragment reference unit.

A first virtual fragment can be formed by segmenting the 3Dreconstruction of the donor skeleton at a location adjacent to the firstvirtual cutting guide. The first virtual fragment can be superimposed onthe second 3D reconstruction of the recipient skeleton.

At step 310, a surgeon can perform an osteotomy on the donor skeleton toremove the first fragment but cutting the skeleton along a cutting pathdefined by the first cutting guide. Upon transferring the removedskeletal fragment from the donor, the first cutting guide can betracked, by the second tracker, for example, when the fragment isbrought near the recipient for attachment. The surgeon can then navigateplacement of the cutting guide as it is dynamically tracked at step 311,and will receive feedback from the system such as by referring to afirst virtual fragment that is superimposed on the second 3Dreconstruction to form a hybrid 3D reconstruction. At step 312, thefirst fragment can then be attached to the recipient skeleton via knownsurgical methods and the incisions can be sutured in step 314.

The step of superimposing the first virtual fragment on the second 3Dreconstruction of the recipient skeleton can include performing anautomated cephalometric computation for the hybrid reconstruction. Infact, the step of superimposing the first virtual fragment on the second3D reconstruction can include providing a communications link between afirst workstation on which the first 3D reconstruction is displayed anda second workstation on which the second 3D reconstruction is displayed,and initiating a data transfer protocol that causes the firstworkstation and the second workstation to send electronic signalsthrough the communications link.

Surgical methods of the embodiments described above can also includeattaching a second cutting guide at a preselected location on therecipient skeleton. The second cutting guide can also include featuresof the cutting guide described above.

For the surgical methods of embodiments described herein the donorskeleton can include a male skeleton or a female skeleton and therecipient skeleton can include a female skeleton. Alternatively, thedonor skeleton can include a male or female skeleton and the recipientskeleton can include a male skeleton.

Surgical methods of the embodiments can further include steps forassessing a size-mismatch between the donor skeleton and the recipientskeleton by measuring a dorsal maxillary interface between the firstfragment and recipient skeleton. In an embodiment, the surgical methodcan include selecting a location of the first fragment onto therecipient skeleton that minimizes dorsal step-off deformity at the areaof osteosynthesis. In an embodiment, the first cutting guide, the secondcutting guide, or both the first cutting guide and the second guide maybe or include concentric cutting guides.

Surgical methods of embodiments can further include mapping the vascularsystem on the facial anatomy of both the recipient and the donor andsuperimposing corresponding virtual representations of the vascularsystem and the facial anatomy onto the first 3D representation, such asshown in FIG. 4B

Surgical methods of embodiments can include a method for registration ofa preoperative model, for example a model reconstructed from CT data, todonor and recipient anatomy. Such a method can include: creating aplurality of indentations on the donor skeleton, creating a plurality ofvirtual markers on the first 3D reconstruction of the donor skeletoncorresponding to the locations of the indentations on the donorskeleton, placing a trackable object on at least one of the plurality ofindentations, and determining whether a subsequent location of thevirtual markers is within a predetermined tolerance relative to anactual subsequent location of the indentations.

EXAMPLES Example 1

Live transplant surgeries (n=2) between four size-mismatched swineinvestigated whether or not an embodiment could actually assist asurgical team in planning and executing a desired surgical plan. Asshown in FIGS. 9A-9B, the first live surgery confirmed the proposedutility of overcoming soft and hard tissue discrepancies related tofunction and aesthetics. The final occlusal plane within the firstrecipient was ideal and consistent with the virtual plan as seen onlateral cephalogram as shown in FIG. 10C. Pre-operative functionalpredictions of donor-to-recipient occlusion were realized based oncephalometric analyses as shown in FIG. 9C performed both before andafter surgery. Soft tissue inconsistencies of the larger-to-smallerswine scenario were also reduced following the predicted movements offace, jaw and teeth as shown in FIG. 10D.

The second live surgery showed improved success as compared to itspredecessor due to surgeon familiarity and technology modifications.System improvements and growing comfort of the surgeons led to reducedoperative times for both donor and recipient surgeries. Overall thesurgical time reduced from over 14 hours to less than 8 hours due toimproved surgical workflow and increased comfort with a system of anembodiment.

Based on the results obtained in the live and plastic bone surgeries,the functions associated with setting up a system of an embodiment(attaching references, performing registration, attaching cuttingguides) adds about 11 minutes to the total length of surgery.

The system also recorded information, such as rendering informationwhich can be stored in a storage medium of a workstation, relating thedonor fragment 1002 to the recipient 1010 qualitatively as shown bycolor mismatch 1004, which matched the post-operative CT data as shownin FIG. 10. The recipient cutting guide 1107′ was not placed as planned1107 due to an unexpected collision between the cranial reference mountand the recipient cutting guide as shown in FIGS. 11A-11B. In this case,there was anterior translation of the cutting guide (toward the tip ofthe swine's snout) by approximately 4 cm.

Overall, the donor 1106 and recipient craniums (n=4) 1108 wereregistered successfully to the reference bodies for both live surgeries.The model to patient registration error across the surgeries was 0.6(+/−0.24) mm. The cutting guide designs of the embodiments proved highlyuseful in carrying out the planned bone cuts, which compensated forsize-mismatch discrepancies between donor and recipient. Marking spheresfixated to the guides allowed real-time movement tracking and “on-table”alloflap superimposition onto the recipient thereby allowingvisualization of the final transplant result.

Example 2

Female and male donor heads (n=2), double-jaw, Le Fort III-basedalloflaps were harvested using handheld osteotomes, a reciprocating saw,and a fine vibrating reciprocating saw. Both osteocutaneous alloflapswere harvested using a double-jaw, Le Fort III-based design (acraniomaxillofacial disjunction), with preservation of the pterygoidplates, incorporating all of the midfacial skeleton, complete anteriormandible with dentition, and overlying soft tissue components necessaryfor ideal reconstruction.

Prior to transplantation, both scenarios were completed virtually giventhe gender-specific challenges to allow custom guide fabrication asshown in panels A-H of FIG. 12. Once assimilated, the donor orthognathictwo-jaw units were placed into external maxilla-mandibular fixation(MMF) using screw-fixated cutting guides to retain occlusalrelationships during the mock transplants as shown in panels A-D of FIG.13.

As shown in FIGS. 13, 14A-14B, an embodiment of a cutting guide 1307 caninclude a frame 1307′ with at least one attachment surface 1319, forexample 1 to 6 attachment surfaces, configured for attaching the cuttingguide to a skeletal feature. The cutting guide can include a navigationsurface 1317 (not shown in FIG. 13) connected to the frame. Thenavigation surface can include a reference geometry that can be trackedby a tracker, for example, via IR optical tracking. The at least oneattachment surface 1319 can include a contoured surface corresponding tocontours of portions of the skeletal feature, for example, such as thecontours of a skeletal feature that intersect a planned-cut plane asindicated by 1319′ in FIG. 12. The at least one attachment surface 1319can be detachably connected to a skeletal feature. The at least oneattachment surface 1319 can be detachably connected to an attachmentguide 1341. The attachment guide 1341 can be detachably connected to aportion of the frame 1307′. For example, attachment guides 1341 can bedetachably connected via slots integrated into frame 1307′, or held inplace against frame 1307 with screws or the like. In another embodiment,attachment guides 1341 are formed as portions of frame 1307′ but can beremoved. The frame can have a ring-like shape (as shown in FIG. 13) orcan have a cylinder-like shape (as shown in FIG. 14A). Frame 1307′having a cylinder like shape can have a bottom surface 1307″ that restsagainst a patient's soft tissue to provide support for the frame.

For example, during a surgical procedure, 3D reconstructions of portionsof a donor skeleton are created. Planned cutting planes are selected anda cutting guide with attachment surfaces having a contoured surfacecorresponding to contours of portions of the skeletal feature, forexample, such as the contours of a skeletal feature that intersect aplanned-cut plane, is designed. The designed cutting guide ismanufactured via, for example, an additive manufacturing process. Thedesigned cutting guide with an integrated navigation surface is attachedto the patient. For example, the cutting guide can be designed such thatit has a snap-on fit over the skeletal feature, which can be furthersecured to the skeletal feature with set screws. A surgeon removes adonor skeletal fragment with the cutting guide attached to the fragment.The donor skeletal fragment is then attached to the recipient. As thedonor skeletal fragment is attached to the recipient, the attachmentsurfaces are removed from the donor fragment. For example, each of theattachment guides 1341 with a corresponding attachment surface 1319 canbe detached from the frame 1307′. As this occurs, a cylindrical shapedframe 1307′ has a bottom surface 1307″ that rests against the softtissue of the patient to provide stability for the remaining portions ofthe cutting guide and to hold the navigation surface 1317′ in place.

While the invention has been illustrated respect to one or moreimplementations, alterations and/or modifications can be made to theillustrated examples without departing from the spirit and scope of theappended claims. In addition, while a particular feature of theinvention may have been disclosed with respect to only one of severalimplementations, such feature may be combined with one or more otherfeatures of the other implementations as may be desired and advantageousfor any given or particular function. For example, the embodimentsdescribed herein can be used for navigation and modeling for osteotomyguidance during double-jaw face transplantation, single-jawmaxillofacial transplantation, and any other neurosurgical, ENT/head andneck surgery, or oral maxillofacial surgical procedure alike.

Embodiments described herein can include platforms for preoperativeplanning and intraoperative predictions related to softtissue-skeletal-dental alignment with real-time tracking of cuttingguides for two mismatched jaws of varying width, height and projection.Additional safeguards, such as collection of confidence points, furtherenable intraoperative verification of the system accuracy. This, inaddition to performing real-time plan verification via tracking anddynamic cephalometry, can considerably increase the robustness of thesystems described herein. Moreover, systems of embodiments can include amodular system that allows additional functionality to be continuallyadded.

Embodiments described herein can include an approach for resolvingconflicts in case of position discrepancies between the placement of theguide and the guide position prompted by the navigation software. Suchdiscrepancy may be due to either the guide (soft tissue interference,iatrogenic malpositioning, changes since the CT data was obtained orimperfections in cutting guide construction/printing), and/or thenavigation system (e.g. registration error, or unintended movement ofthe kinematic markers). To resolve these source(s) of discrepancy, fourindentations can be created on a bone fragment (confidence points) wherea reference kinematic marker is attached. At any time during anoperation, a surgeon can use a digitizer and compare the consistency ofthe reported coordinates of the indentations via navigation to theircoordinates with respect to a virtual computer model.

Embodiments described herein can include a system that providesreal-time dynamic cephalometrics and masticatory muscle biomechanicalsimulation for both planning and intraoperative guidance to ensure idealoutcomes in craniomaxillofacial surgery.

Additional Embodiments

Osseointegrated Dental Implants

Patients with poor or missing dentitions may require dental implants toimprove mastication. A popular modality with increasing indicationsincludes “osseointegrated dental implants”. Osseointegrated dentalimplants can include, and may consist of, a two-piece permanent implantdevice, which is placed into either the maxilla or mandible skeletonwith a power drill for placement and stability. A second piece, in theshape of a tooth is screwed onto the secure base. An embodiment of theCAPE system described above can be used to provide the dentist orsurgeon real-time cephalometric feedback in an effort to restore idealocclusion and predict optimized mastication with biomechanicalpredictions—as similar to maxillofacial transplantation. As such, thedentist or surgeon placing these items needs to know the bone stockquality of the jaw(s) and angle to place the framework.

Osseointegrated Craniofacial Implants and Prosthetics

Patients with severe cranial or facial disfigurement may benefit fromcustom implant reconstruction or be poor surgical candidates due tooverwhelming co-morbidities and/or because of an accompanying poorprognosis. Therefore, to help return these patients into society, someuse craniofacial implants or prosthetics as a way to restore “normalcy”.Application of these three-dimensional implants and prostheticsreplacing absent craniofacial features (i.e., skeletal, nose, eye, etc)may either be hand-molded/painted by an anaplastologist or printed with3D technology by a craniofacial technician. Either way, in anembodiment, the CAPE system described above can provide a one-stopsolution for patients requiring alloplastic and/or bioengineeredprosthetic reconstruction for large craniomaxillofacial deformities. Thecraniofacial implants can be tracked as similar to a donorface-jaw-teeth segment described above. For example, pre-placementimages of the implant or prosthetic onlay may be fabricated, andsurgical plans may be optimized since these appliances are placed withosseointegrated devices as similar to dental implants describedabove—with rigid plates and screws. As such, the surgeon placing themneeds to know the exact location, underlying bone stock quality, andangle to place the framework, and desires unprecedented visual feedbackas to the ideal position in three-dimensional space.

Craniomaxillofacial Trauma Reconstruction

Patients suffering from acute or chronic facial disfigurement are oftenseen by a craniomaxillofacial surgeon. Both penetrating and/or blunttrauma may cause significant damage to the underlying facial skeleton.As such, in an embodiment, the CAPE system technology described hereinallows the surgeon to assess and optimize bone fragment reduction andreconstruction with real-time feedback. In addition, fractures affectingthe jaws can be aided by real-time cephalometrics in hopes to restorethe patient back to their pre-trauma angle/measurements (as a way toassure proper occlusion). Navigation, as described above in anembodiment of the CAPE system, can be exceptionally helpful for orbitfractures around the eye or cranial fractures around the brain, sincethe nerve anatomy is delicate and consistent—which makes it applicableto the CAPE system. In summary, a surgeon (including the likes of aPlastic surgeon, ENT surgeon, oral/OMFS surgeon, oculoplastic surgeon,neurosurgeon) reducing craniofacial fractures needs to know the bonestock quality remaining, where plates/screws are best placed, and theoptimal plan prior to entering the operating room.

Neurosurgical Procedures

Neurosurgeons frequently perform delicate craniotomies for access forbrain surgery. Currently, there are several navigational systemsavailable. However, none of the conventional systems include featuresdescribed in the embodiments of the CAPE platform as described above.That is, the conventional systems lack the ability to assist bothpre-operatively with planning AND with intra-operative navigation forexecution assistance. In addition, the current neurosurgery systemsrequire the head to be placed in antiquated “bilateral skull clamp pins”during the entire surgery. This means that before each neurosurgeryprocedure starts, a big 3-piece clamp is crunched onto the skull of thepatient to make sure the head does not move during surgery, particularlyto allow for use of the conventional navigation systems. However,embodiments of the CAPE system, such as those described above, use asmall, modified rigid cranial reference mount which removes the need forusing a big, bulky clamp from the field and allows the surgeon to rotatethe patient's head if and when needed. To a craniofacial plasticsurgeon, who often is consulted to assist with simultaneous scalpreconstruction, elimination/removal of such pins from the surgical fieldis a huge advantage. For example, elimination of the pins makes scalpreconstruction in the setting of neurosurgery much safer since the pinsaren't present to hold back mobilization and dissection of the nearbyscalp, which is needed often for complex closure. It also, reduces therisk of surgical contamination since the current setup with pins isbulky and makes surgical draping and sterility much more difficult andawkward. A small cranial mount as part of the CAPE system is a hugeadvancement for the field.

Congenital Deformity Correction

Unfortunately, newborns are commonly born with craniofacial deformitiesto either maternal exposure or genetic abnormalities. As such, they mayhave major development problems with their skeleton and the overlyingstructures (eyes, ears, nose) may therefore appear abnormal. Inaddition, newborns may suffer from craniosynostosis (premature fusing oftheir cranial sutures) which causes major shifts in the shape of theirhead at birth. In an embodiment, the CAPE system described above, can beutilized to address such congenital deformities, irrespective ofetiology. For example, if a 16 year old needs to have major Le Fortsurgery to move the central facial skeleton into better position forwardto improve breathing, mastication, and appearance, use of the CAPEsystem technology for both pre- and intra-operatively provides a hugeadvancement for the field.

Head/Neck and Facial Reconstruction (ENT Surgery)

Head and neck surgeons in the specialty of Otolarygology (ENT) arefrequently reconstructing facial skeletons. Reasons include post-tumorresection, facial trauma, aesthetic improvement, congenital causesand/or functional improvement (nose, mouth, eyes, etc). Therefore, thisspecialty would greatly benefit from use of the CAPE system technologydescribed herein. For example, in an embodiment, use of the CAPE systemcan be used in a wide range of surgeries including such instances aspost-trauma fracture reduction/fixation, free tissue transfer planningand execution (i.e., free flap reconstruction with microsurgical fibulaflaps for large bone defects where the leg bone receives dental implantsfor jaw reconstruction), smaller jaw reconstruction cases with implantmaterials, and/or anterior skull base reconstructions with neurosurgeryfollowing tumor resection. This specialty is very diverse, and thereforethe CAPE system's easy adaptability can help make it greatly valuable tothis group of surgeons.

Orthognathic Surgery

Orthognathic surgery describes any of surgical procedure type moving thejaw and/or jaw-teeth segments. This is most commonly performed by eitheroral surgeons, oral-maxillofacial surgeons (OMFS), or plastic surgeons.It is done currently both in the hospital as an insurance case or in theoutpatient setting for a fee-for-service. It may be indicated forenhanced mastication, improved aesthetics, and/or both reasons. Havingthe ability to plan and predict jaw movements based on biomechanicalmuscle (i.e., external) forces will be immensely valuable to this field.In an embodiment, surgeons can utilize the CAPE system described aboveto predict functional jaw movements both at time of surgery and aftersurgery (1, 5, 10, 20 years post-op). In addition, in an embodiment, asurgeon can utilize the CAPE system to provide real-time cephalometricfeedback, which provides an advancement not seen in the conventionalsystems. In comparison, for the last several centuries, oral surgeonshave used splints fabricated in the dental lab pre-operatively forassistance in the operating room to help confirm dental alignment asplanned. This takes time (e.g., 4-6 hours to make by hand), effort, andmoney. In contrast to the conventional systems, surgeons utilizing theCAPE system can go to the operating room with pre-fabricated cuttingguides and tracking instruments, cut the jaws where planned, and thenmatch the teeth on the table based on real-time cephalometric feedbackand biomechanical jaw simulation to predict post-operativemastication—unlike ever before. For example, use of the CAPE system willallow surgeons to know instantaneously if the aesthetic and functionalangles/measurements are ideal and where they should be. In addition, theCAPE system is able to supply palatal cutting guides and pre-bent metalfixation plates (as opposed to the conventional methods that requirehand bending each plate for proper shape). In summary, the CAPE systemwill be a “game-changer” for orthognathic surgery.

“Computer-Assisted Cranioplasty”

At least some embodiments described herein can be used for the immediatesurgical repair of large cranial defects (e.g., >5 cm²). For example,embodiments described herein may be used for designing, forming andimplanting customized craniofacial implants following benign/malignantskull neoplasm (tumor) resection (i.e., referred to as “single-stageimplant cranioplasty”). Currently, it is challenging to reconstruct suchpatients with pre-fabricated implants using conventional methods sincethe actual size/shape of the defect site is unknown until the tumor isremoved. Accordingly, use of a computer-assisted surgical system of anembodiment may significantly reduce the intraoperative time used forreshaping/resizing the customized implant. For example, embodimentsprovide visualization related to the tumor, the resulting skull defect,and the reshaped implant for exact positioning. In other words, in anembodiment, a Computer-Assisted Planning and Execution (CAPE) systemthat can be utilized for Le Fort-based, Face-Jaw-Teeth transplantationmay also be used for improving both the pre-operative planning andintra-operative execution of single-stage implant cranioplasties.Cranioplasties may be performed to reconstruct large defects followingstroke, trauma, aneurysmal bleeding, bone flap removal for infection,and oncological ablation. However, oncological defects are commonlyreconstructed with “off-the-shelf” materials, as opposed to using apre-fabricated customized implant—simply because the exact defectsize/shape is unknown. With this in mind, embodiments described hereininclude a computer-assisted algorithm that may allow surgeons toreconstruct tumor defects with pre-customized cranial implants (CCIs)for an ideal result.

Nearly 250,000 primary brain tumors/skull-based neoplasms are diagnosedeach year resulting in a range of 4500-5000 second-stage implantcranioplasties/year. Unfortunately, the common tumor defect cranioplastyis reconstructed with on-table manipulation of titanium mesh, liquidpolymethylmethacrylate (PMMA), liquid hydroxyapatite/bone cement (HA) orautologous split-thickness calvarial bone grafts (ref), which forces thesurgeon to shape/mold these materials to an approximate size/shape.Expectingly, this results in some form of craniofacial asymmetry and apost-operative appearance which is suboptimal. Furthermore, thedifficult shaping process may take several hours—which in turn increasesanesthesia, total blood loss, risk for infection, morbidity, and allcosts associated with longer operative times. Therefore, there issignificant opportunity to extend this CAPE to thousands of patients.

In the year 2002, the advent of computer-aided design and manufacturing(CAD/CAM) was used for the first time to pre-emptively match thecontralateral, non-operated skull for ideal contour and appearance,which provided for the use of CCIs. However, cranioplasties with suchCCIs can only be performed as “second stage” operations during which aclinician, such as a surgeon, ensures that the CCI fits perfectly intothe skull defect. Recent developments have demonstrated the feasibilityof CCIs for “single-stage cranioplasty”, but this involves using ahandheld bur to shave down the pre-fabricated implant artistically.However, challenges in both assessing and predicting eachtumor-resection deformity pre-surgery still limits the applicability ofCCIs in this patient population. For example, challenges such as 1)unknown exact tumor size, 2) unknown growth from time of pre-op CTscan-to-actual day of surgery, and 3) the unknown resection marginsneeded to minimize local recurrence. For these cases, the CCI would needto be reshaped/resized intraoperatively from a size slightly larger thanexpected—which is a process that may take several (2-4) hours. However,there are no established planning and execution systems available toassist these single-stage reconstructions. Accordingly, embodimentsdescribed herein may be used by surgeons in performing single-stagecranioplasty following oncological resection. In other words,embodiments include algorithms for real-time updates related tosingle-stage customized implant cranioplasty. For example, in anembodiment, there is a Computer-Assisted Planning and Execution (CAPE)system, which is a SINGLE, seamless platform capable of being used forboth planning (pre-op use) and navigation (intra-op use) which overcomesthe limitations of conventional systems that do either one or the other.In addition, embodiments include novel hardware such as trackablecutting guides and rigid cranial reference mount.

Computer-Assisted Transplantation System

In an embodiment, there is a computer-assisted transplantation system1500 such as the system 2000 depicted in FIGS. 15A-15G and describedabove. It is noted that components of system 2000 may be combined withor interchanged with components of system 200 illustrated in FIGS.2A-2G. The system can include a donor sub-system 2000-D and a recipientsub-system 2000-R. The donor sub-system may include a first referenceunit 2005-D having a first trackable element 2001-D which may beintegrated with, attached to, or detachably connected to a mount, suchas a cranial reference mount 2003-D. The first reference unit 2005-D maybe attached at a predetermined location on a donor being 2006 anatomy,such as a predetermined skeletal feature 2009-D, for example, a locationof the donor's skull. The donor sub-system 2000-D may also include afragment reference unit having a second trackable element 2001-D′. Thefragment reference unit may be attached on a predetermined location onthe donor being 2006 anatomy, such as at a predetermined location on aportion 2011-D of the donor being's anatomy that is to be fragmentedfrom the donor being and transplanted onto a recipient being. The donorsub-system 2000-D may also include a first detector 2013-D that may beconfigured to provide at least one of a first signal 2091 as shown inFIG. 15H corresponding to a detected location of one or more of thefirst trackable element 2001-D and the second trackable element 2001-D′.

The recipient sub-system 2000-R may include a second reference unit2005-R having a third trackable element 2001-R. The second referenceunit 2005-R may be attached at a predetermined location on a recipientbeing 2008 anatomy, such as at a predetermined skeletal feature 2009-R,for example, a location 2010 of the recipient's skull via a mount suchas a cranial reference mount 2003-R. The recipient sub-system 2000-R mayalso include a second detector 2013-R configured to provide at least oneof a second signal 2093, as shown in FIG. 15H, corresponding to adetected location of at least the third trackable element 2001-R.

The donor sub-system 2000-D may further include a cutting guide 2007-Dhaving a fourth trackable element 2017-D. The cutting guides describedherein may be a surgical guide assembly having an attachment deviceconfigured to be coupled to a bone. A cut location indicator is coupledto the attachment device. The cut location indicator identifies alocation where the bone is to be cut. An arm is coupled to theattachment device, the cut location indicator, or both. A supportstructure is coupled to the arm. The support structure is configured tohave a tracking element coupled thereto.

The donor sub-system may further include a first computer 2015-D thatreceives the at least one first signal 2091. The recipient sub-system2000-R may further include a second computer 2015-R that receives the atleast one second signal 2093. The at least one first signal 2091 and theat least one second signal 2093 may be communicated between thedetectors and computers via a communications link, as indicated by thedashed double-headed arrow in FIG. 15F, which may include datatransmission wires and/or wireless transmissions either of which may becommunicated through a network, such as a LAN or WAN network, includingcommunication over an intranet or over the internet, including TCP/IPdata transfer. In an example, a communications link allows the firstcomputer 2015-D and the second computer 2015-R to communicate with oneanother.

The first detector 2013-D, the second detector 2013-R, or both may be anoptical tracker, a magnetic tracker or both an optical tracker and amagnetic tracker as generally shown in FIG. 15G as 2013, and may beutilized in the system to perform a detecting function, as indicated bythe double-headed arrow in FIG. 15, for detecting locations of items.Optical trackers typically emit and capture light in the invisible(infrared) electromagnetic spectrum. Trackable fiducials used with thesesystems can include passive (i.e., reflective) or active (i.e., thosethat actively emit infrared light) markers. Using specific geometriesknown to the camera, the pose of a reference can be tracked through thefield of view. An example system is the NDI Polaris available fromNorthern Digital, Inc. (Ontario, Canada). Magnetic trackers rely on amagnetic field generator and (typically) a passive coil architecture.The field generator creates a time-varying field, which induces acurrent in the passive sensor. This current is measured and, through acalibration procedure, used to identify up to a 6-dof pose of thesensor. An example system is the NDI Aurora available from NorthernDigital, Inc. (Ontario, Canada).

One or more of the first trackable element 2001-D, the second trackableelement 2001-D′, the third trackable element 2001-R, and the fourthtrackable element 2017-D may be an IR reflector or an IR emitter, asgenerally shown as 2001 in FIG. 15D, each of which may be detachablyconnected to an attachment surface such as a mount, including a cranialreference mount 2003, which may form part of a reference unit 20005 asgenerally shown in FIG. 15E. As an example, an IR reflector may be adetachably connected surface, such as a sphere. As an example, an IRemitter may be a light emitting diode configured to emit infrared light.

The first and second computers may be selected from a desktop computer,a network computer, a mainframe, a server, or a laptop. The first andsecond computers may be configured to access at least one computerreadable reconstruction of at least one object, such as a being'sanatomy, or at least portions of the being's anatomy, for example, afirst computer readable reconstruction 2081-D and a second computerreadable reconstruction 2801-R. The computer readable reconstruction mayinclude three-dimensional (3D) views, such as those created by scanninga patient via, for example, CT scan. At least one display, such as afirst display 2015-D′ may be connected to the first computer 2015-D. Thedisplay may be configured to represent the computer readablereconstruction. The first computer may include at least one memory tostore data and instructions, and at least one processor configured toaccess the at least one memory and to execute first instructions 1600.

First instructions 1600 may include one or more of the steps included inthe flowchart on FIG. 16. For purposes of providing examples, some ofthe steps are described below with reference to components of system2000 from FIGS. 15A-15G. In an embodiment, first instructions 1600include accessing a first computer readable reconstruction of a donoranatomy at 1601, and displaying the first computer readablereconstruction on at least one display at 1602, such as the firstdisplay 2015-D′. The first computer readable reconstruction may includea first orientation that is updated based on a physical location of atleast one of the first trackable element 2001-D and the second trackableelement 2001-D′ as detected by the first detector 2013-D. The firstinstructions 1600 may further include superimposing a planned cuttingplane (such as cutting plane 403 of FIG. 4A) on the first computerreadable reconstruction at 1603. The first instructions 1600 may furtherinclude generating a first virtual cutting guide 2083-D having ageometry that corresponds to an interface between intersecting portionsof the planned cutting plane and the first computer readablereconstruction at 1604.

The first instructions 1600 may further include controlling at least onedevice for manufacturing a cutting guide, such as cutting guide 207-D,according to the geometry of the first virtual cutting guide 2083-D at1604. The device may be any manufacturing device that fabricates anobject based on instructions, such as computer readable instructions,for example, instructions provided in digital data, including any devicethat utilizes additive or subtractive manufacturing technologies, suchas those that fabricate an object from appropriately approved materialsfor medical use. Accordingly, the at least one device may be an additivemanufacturing device, such as a 3D printer, or another kind ofmanufacturing device, including subtractive manufacturing device, suchas a CNC machine. Examples of additive manufacturing technologies mayinclude vat polymerization (e.g., PROJET® 6000, 7000, 8000 availablefrom 3D Systems Corp., Rock Hill, S.C.), materials jetting (e.g., Objet500 or Eden 250, each available from Stratasys, Ltd., Eden Prairie,Minn.), powder binding (e.g., PROJET® 460, 650 available from 3D SystemsCorp., Rock Hill, S.C.), powder fusion (e.g., EBM® available from ArcamAB, Sweden), material extrusion (Fortus 250, 400, available fromStratasys, Ltd., Eden Prairie, Minn.), or any one denoted by the ASTMF42 committee on additive manufacturing. Accordingly, system 2000 mayinclude a device (not shown) for manufacturing components, such ascutting guides, reference units and/or the trackable elements, and thedevice may be connected to at least one of the first computer and thesecond computer via the communications link described above. The firstinstructions may also include generating a computer readable file thatcontains instructions for manufacturing the cutting guide, and/orcontains dimensions of a cutting guide based on the geometry of thefirst virtual cutting guide.

The first instruction 1600 may also include forming a first virtualfragment 2011-D by, for example, segmenting the computer readablereconstruction of the donor anatomy along portions of the computerreadable reconstruction that intersect with the planned cutting plane,at 1605. In an embodiment, the first virtual fragment 2011-D may includea third orientation that is updated based on a physical location of atleast one of the first trackable element 2001-D and the second trackableelement 2001-D′ as detected by the first detector 2013-D.

In an embodiment, at least one display, such as a second display 2015-R′is connected to a second computer, such as second computer 2015-R. Thesecond computer may include at least one memory to store data andinstructions, and at least one processor configured to access the atleast one memory and to execute second instructions 1700.

Second instructions 1700 may include one or more of the steps includedin the flowchart on FIG. 17. For purposes of providing examples, some ofthe steps of instructions 1700 are described with reference tocomponents of system 2000 from FIGS. 15A-15H. The second instructions1700 may include accessing a second computer readable reconstruction ofa recipient anatomy, such as second computer readable reconstruction2081-R at 1701. Second instructions 1700 may further include displayingthe second computer readable reconstruction on the at least one display,such as the second display 2015-R at 1702. The second computer readablereconstruction may include a second orientation that is updated based ona physical location of the third trackable element 2001-R as detected bythe second detector 2013-R.

During a surgical procedure, such as a transplantation of a anatomicalfeature from a donor being onto the anatomy of a recipient being, it isuseful to track the location of the fragment relative to the anatomy ofthe recipient being before, during and/or after the transplantation.Accordingly, in the system 2000, the second signal 2093 may furthercorrespond to a location of the second trackable element 2001-D asdetected by the second detector 2013-R. Thus, the second instructions1700 may also include superimposing the first virtual fragment 2011-D onthe second computer readable reconstruction 2008 of the recipientanatomy at 1703, for example, with an orientation that is updated basedon a physical location of the second trackable element 2001-D′ and thethird trackable element 2001-R as sensed by the second detector 2013-R.

FIG. 18 is a flow chart depicting a computer-assisted transplantationmethod 1800. The method 1800 may include steps for interacting with, forexample, using the system 2000. In an example, the method can includeattaching a first reference unit comprising a first trackable element toa first anatomical feature of a donor being at 1801. The method 1800includes attaching a fragment reference unit comprising a secondtrackable element to a second anatomical feature of the donor at 1802.The method 1800 includes detecting a location of at least one of thefirst trackable element and the second trackable element with a firstdetector at 1803. As described above, the first detector may beconfigured to provide at least one of a first signal corresponding tothe detected location of at least one of the first trackable element andthe second trackable element. The method 1800 may include accessing afirst computer readable reconstruction of the donor anatomy at 1804. Asdescribed above, the first computer readable reconstruction may includea first orientation that is updated based on a physical location of atleast one of the first trackable element and the second trackableelement as detected by the first detector. The method 1800 may includeattaching a second reference unit comprising a third trackable elementto an anatomical feature of a recipient being at 1805. The method 1800may include detecting a location of the third trackable element with asecond detector at 1806. As described above, the second detector may beconfigured to provide at least one of a second signal corresponding to adetected location of at least the third trackable element. The method1800 may also include accessing a second computer readablereconstruction of the recipient anatomy at 1807. As described above, thesecond computer readable reconstruction may include a second orientationthat is updated based on a physical location of the third trackableelement detected by the second detector. The method 1800 may includesuperimposing a first virtual donor fragment of the first computerreadable reconstruction on the second computer readable reconstructionat 1808. The method 1800 may also include attaching a second cuttingguide at a preselected location on the recipient anatomy at 1809. Thesecond cutting guide may be formed according the methods describedabove, except may be based on a geometry of an intersection of a plannedcutting plane that is superimposed on the second computer readablereconstruction of the recipient's anatomy. In other words, the secondcutting guide may be custom designed for attaching on the recipientsanatomy. Accordingly, the second cutting guide may include an attachmentsurface configured for attaching to an anatomical feature and a fifthtrackable element. Accordingly, the second signal may further correspondto a detected location of the fifth trackable element.

The method 1800 may also include accessing a computer readablereconstruction of the recipient being's vascular system and facialanatomy at 1810, accessing a computer readable reconstruction of thedonor being's vascular system and facial anatomy at 1811, andsuperimposing the computer readable reconstruction of the donor being'svascular system and facial anatomy onto the first computer readablereconstruction at 1812.

The described method may be utilized during a surgical procedure, suchas a surgical transplantation procedure or an implant-basedcranioplasty. Accordingly, there is a donor being (or a custom, 3Dcraniofacial implant made of either alloplastic materials or biologictissue engineered cells—which is analogous to the donor's face-jaw-teethsegment in this case) and a recipient being on whom the surgicalprocedure is performed. In an example, the donor provides an anatomicalfeature and the recipient receives the anatomical feature. In anexample, the donor being is a male being and the recipient is a femalebeing. In an example, the donor being is a female being and therecipient is a male being. In an example, the donor and the recipientare the same sex. Although in some transplantations, the donor being andrecipient being are two separate beings, the invention is not solimited. Accordingly, in an example the donor being and the recipientbeing may be i) the same being, or ii) different beings.

FIG. 19 is a flow chart depicting a computer-assisted transplantationmethod 1900 which may include all the steps of method 1800, for example,including step 1801. The method 1900 may also include superimposing aplanned cutting plane on the first computer readable reconstruction at1901, and forming a cutting guide at 1902. As described above for system2000, the cutting guide may include at least one attachment configuredin a geometry defined by intersecting portions of the planned cuttingplane and the first computer readable reconstruction. Additionally, thecutting guide may further include a fourth trackable element. Asdescribed above, the second signal may further correspond to a detectedlocation of the fourth trackable element. The method 1900 may alsoinclude attaching the cutting guide at a location on the donor anatomyat 1903, tracking a location of the fourth trackable element with thefirst detector at 1904, and superimposing a first virtual cutting guideon the first computer readable reconstruction at 1905. As describedabove for system 2000, the first computer readable reconstruction mayhave an orientation that is updated based on at least one of the firsttrackable element, the second trackable element and the fourth trackableelement. The method 1900 may also include forming a first virtual donorfragment at 1906, for example, by segmenting the first computer readablereconstruction at an interface of the planned cutting plane and thefirst computer readable reconstruction. The method 1900 may also includesuperimposing the first virtual fragment on the second computer readablereconstruction to form a hybrid computer readable reconstruction at1907.

The method 1900 may further include performing an osteotomy on the donoranatomy at 1908. The osteotomy may include, among other steps, cuttingthe donor anatomy along a cutting path defined by the first cuttingguide and removing a first donor fragment from the donor anatomy. Thefirst donor fragment may be separated from the donor anatomy along thecutting path and comprising the second anatomical feature. The method1900 may further include tracking a location of the fourth trackableelement with the second detector at 1909.

The method 1900 may also include assessing a size-mismatch by measuringinconsistent skeletal interfaces between the anatomy of the donor being,for example, by measuring a dorsal maxillary interface, between theanatomy of the donor being and the anatomy of the recipient being at1910, and selecting a location for attaching a donor anatomical featureonto the recipient being that minimizes the size mismatch, such as,step-off deformity, for example, that minimizing the dorsal step-offdeformity, at an area of osteosynthesis at 1911. The method 1900 mayalso include attaching the first donor fragment onto the recipient at1912, for example, to form recipient fragment 2011-R. In an example,superimposing the first virtual fragment on the second computer readablereconstruction of the recipient anatomy may include performing anautomated cephalometric computation for the hybrid reconstruction.

The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “inconnection with,” and “connecting” refer to “in direct connection with”or “in connection with via one or more intermediate elements ormembers.” Furthermore, to the extent that the terms “including”,“includes”, “having”, “has”, “with”, or variants thereof are used ineither the detailed description and the claims, such terms are intendedto be inclusive in a manner similar to the term “comprising.” As usedherein, the phrase “at least one of” or “one or more of”, for example,A, B, and C means any of the following: either A, B, or C alone; orcombinations of two, such as A and B, B and C, and A and C; orcombinations of three A, B and C.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A computer-assisted surgical system forperforming craniomaxillofacial surgery, comprising: an implantsub-system comprising: a first reference unit composed of a trackableelement, and a first detector configured to provide a first signalcorresponding to a detected location of the first reference unit; arecipient sub-system comprising: a second reference unit composed of atrackable element, and a second detector configured to provide a secondsignal corresponding to a detected location the second reference unit;and a first computer and at least one display connected to the firstcomputer, wherein the first computer comprises: at least one memory tostore data and instructions, and at least one processor configured toaccess the at least one memory and to execute first instructions, thefirst instructions comprising: accessing a first computer readablereconstruction of an implant, and displaying the first computer readablereconstruction on the at least one display, wherein the first computerreadable reconstruction comprises a first orientation that is updatedbased on a physical location of the first reference unit as detected bythe first detector.
 2. The system of claim 1, wherein the implantsub-system comprises the first computer that receives the at least onefirst signal, and wherein the recipient sub-system further comprises asecond computer that receives the at least one second signal.
 3. Thesystem of claim 2, further comprising a communications link that allowsthe first computer and the second computer to communicate with oneanother.
 4. The system of claim 1, wherein the first detector, thesecond detector, or both the first and second detectors comprise anoptical tracker, a magnetic tracker or both an optical tracker and amagnetic tracker.
 5. The system of claim 1, wherein one or more of thefirst trackable element, the second trackable element, and the thirdtrackable element comprise an IR reflector or an IR emitter.
 6. Acomputer-assisted method for performing craniomaxillofacial surgery,comprising: attaching a first reference unit comprising a firsttrackable element to an implant; attaching a fragment reference unitcomprising a second trackable element to the implant; detecting alocation of at least one of the first trackable element and the secondtrackable element with a first detector, the first detector configuredto provide at least one of a first signal corresponding to the detectedlocation of at least one of the first trackable element and the secondtrackable element; accessing a first computer readable reconstruction ofthe implant, wherein the first computer readable reconstructioncomprises a first orientation that is updated based on a physicallocation of at least one of the first trackable element and the secondtrackable element as detected by the first detector; attaching a secondreference unit comprising a third trackable element to an anatomicalfeature of a recipient being; detecting a location of the thirdtrackable element with a second detector, the second detector configuredto provide at least one of a second signal corresponding to a detectedlocation of at least the third trackable element; accessing a secondcomputer readable reconstruction of the recipient anatomy, wherein thesecond computer readable reconstruction comprises a second orientationthat is updated based on a physical location of the third trackableelement detected by the second detector; and superimposing the firstcomputer readable reconstruction on the second computer readablereconstruction.
 7. The method of claim 6, further including attachingthe first donor fragment onto the recipient.
 8. The method of claim 7,further comprising: assessing a size-mismatch by measuring inconsistentskeletal interfaces between the implant and the anatomy of the recipientbeing, and selecting a location for attaching the implant onto therecipient being that minimizes a step-off deformity at an area ofosteosynthesis.
 9. The method of claim 6, further comprising performingan automated cephalometric computation, a biomechanical simulation, orboth for the hybrid reconstruction.
 10. The method of claim 6, furthercomprising attaching a second cutting guide at a preselected location onthe recipient anatomy, wherein the second cutting guide comprises: anattachment surface configured for attaching to an anatomical feature anda fifth trackable element; and wherein the second signal furthercorresponds to a detected location of the fifth trackable element. 11.The method of claim 6, further comprising accessing a computer readablereconstruction of the recipient being's vascular system and facialanatomy.